Published: 12 Mar 2024

The standard definition of a reference range (usually referred to if not otherwise specified) basically originates in what is most prevalent in a reference group taken from the population.
Reference range or reference interval usually describes the variations of a measurement or value in healthy individuals. Reference ranges are usually given as what are the usual (or normal) values found in the population, more specifically the prediction interval that 95% of the population fall into. More specifically, optimal levels are generally close to a central tendency of the values found in the population. However, there are also optimal health ranges that are those that appear to have the optimal health impact on people. However, usual and optimal levels may differ substantially, most notably among vitamins and blood lipids, so these tables give limits on both standard and optimal (or target) ranges.It is a basis for a physician or other health professional to interpret a set of results for a particular patient. This may also be called standard range. For most substances presented, the optimal levels are the ones normally found in the population as well. In contrast, optimal (health) range or therapeutic target is a reference range or limit that is based on concentrations or levels that are associated with optimal health or minimal risk of related complications and diseases.

We want you to be informed, but we don't pretend to take the place of communication between you and your health care provider. This remains true even for those tests, such as the components of the basic metabolic panel (BMP), for which we have included reference ranges. Decision limits are values that represent either the upper or lower quantity of an analyte that are consistent with a disease state or indicate a need for treatment.
Blood glucose is an example of an analyte for which decision limits have been established and are widely used by health care providers. Remember, a reference range is merely a guide for your health care provider. If you need further explanation of your results, you should talk to your health care provider. We want you to understand what each test on this site is for, but because we can't be aware of all the factors that could affect your test results, we can't interpret the results without more information. Treatment is required to reduce the risk for cardiovascular disease, kidney disease, and other long-term complications of diabetes.
In this situation, it is a value above a particular limit that provides information rather than a value that falls within or outside a set range of numbers.For adults in a routine setting in which fasting blood glucose testing is done to detect type 2 diabetes, a fasting glucose level of 126 mg/dL (7.0 mmol/L) or above, obtained on more than one testing occasion, indicates diabetes. He or she will interpret the result in the context of your medical history and current presentation - something that no website is yet able to do.
For a small number of tests, long-term studies of certain disease processes have led to the establishment of decision limits that are more useful than reference ranges in determining clinical outcomes and guiding treatment decisions.